Re: [PATCH v2 3/5] hw/nvram/eeprom_at24c: Add init_rom field and at24c_eeprom_init_rom helper

[Peter Delevoryas]

On Tue, Jan 17, 2023 at 08:35:44AM +0100, Cédric Le Goater wrote:
> On 1/17/23 00:56, Peter Delevoryas wrote:
> > Allows users to specify binary data to initialize an EEPROM, allowing users 
> > to
> > emulate data programmed at manufacturing time.
> > 
> > - Added init_rom and init_rom_size attributes to TYPE_AT24C_EE
> > - Added at24c_eeprom_init_rom helper function to initialize attributes
> > 
> > Signed-off-by: Peter Delevoryas <peter@pjd.dev>
> > ---
> >   hw/nvram/eeprom_at24c.c         | 37 ++++++++++++++++++++++++++++-----
> >   include/hw/nvram/eeprom_at24c.h |  2 ++
> >   2 files changed, 34 insertions(+), 5 deletions(-)
> > 
> > diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
> > index 98857e3626b9..bb9ee75864fe 100644
> > --- a/hw/nvram/eeprom_at24c.c
> > +++ b/hw/nvram/eeprom_at24c.c
> > @@ -50,6 +50,9 @@ struct EEPROMState {
> >       uint8_t *mem;
> >       BlockBackend *blk;
> > +
> > +    const uint8_t *init_rom;
> > +    uint32_t init_rom_size;
> >   };
> >   static
> > @@ -131,13 +134,26 @@ int at24c_eeprom_send(I2CSlave *s, uint8_t data)
> >   I2CSlave *at24c_eeprom_init(I2CBus *bus, uint8_t address, uint32_t 
> > rom_size)
> >   {
> > -    I2CSlave *i2c_dev = i2c_slave_new(TYPE_AT24C_EE, address);
> > -    DeviceState *dev = DEVICE(i2c_dev);
> > +    return at24c_eeprom_init_rom(bus, address, rom_size, NULL, 0);
> > +}
> > +
> > +I2CSlave *at24c_eeprom_init_rom(I2CBus *bus, uint8_t address, uint32_t 
> > rom_size,
> > +                                const uint8_t *init_rom, uint32_t 
> > init_rom_size)
> > +{
> > +    EEPROMState *s;
> > +
> > +    s = AT24C_EE(qdev_new(TYPE_AT24C_EE));
> > +
> > +    qdev_prop_set_uint8(DEVICE(s), "address", address);
> > +    qdev_prop_set_uint32(DEVICE(s), "rom-size", rom_size);
> > -    qdev_prop_set_uint32(dev, "rom-size", rom_size);
> > -    i2c_slave_realize_and_unref(i2c_dev, bus, &error_abort);
> > +    /* TODO: Model init_rom with QOM properties. */
> 
> ok. This can be fixed with a property later when we have support.
> 
> > +    s->init_rom = init_rom;
> > +    s->init_rom_size = init_rom_size;
> > -    return i2c_dev;
> > +    i2c_slave_realize_and_unref(I2C_SLAVE(s), bus, &error_abort);
> > +
> > +    return I2C_SLAVE(s);
> >   }
> >   static void at24c_eeprom_realize(DeviceState *dev, Error **errp)
> > @@ -162,7 +178,14 @@ static void at24c_eeprom_realize(DeviceState *dev, 
> > Error **errp)
> >           }
> >       }
> > +    if (ee->init_rom_size > ee->rsize) {
> > +        error_setg(errp, "%s: init rom is larger than rom: %u > %u",
> > +                   TYPE_AT24C_EE, ee->init_rom_size, ee->rsize);
> > +        return;
> > +    }
> > +
> >       ee->mem = g_malloc0(ee->rsize);
> > +
> >   }
> >   static
> > @@ -185,6 +208,10 @@ void at24c_eeprom_reset(DeviceState *state)
> >           }
> >           DPRINTK("Reset read backing file\n");
> >       }
> > +
> > +    if (ee->init_rom) {
> > +        memcpy(ee->mem, ee->init_rom, MIN(ee->init_rom_size, ee->rsize));
> > +    }
> 
> I don't think we can have both an init_rom and a drive. The realize
> handler should report an error in that case.

+1, I'll include that in v3.

> 
> >   }
> >   static Property at24c_eeprom_props[] = {
> > diff --git a/include/hw/nvram/eeprom_at24c.h 
> > b/include/hw/nvram/eeprom_at24c.h
> > index 79a36b53ca87..e490826ab1d0 100644
> > --- a/include/hw/nvram/eeprom_at24c.h
> > +++ b/include/hw/nvram/eeprom_at24c.h
> > @@ -6,5 +6,7 @@
> >   #include "hw/i2c/i2c.h"
> >   I2CSlave *at24c_eeprom_init(I2CBus *bus, uint8_t address, uint32_t 
> > rom_size);
> > +I2CSlave *at24c_eeprom_init_rom(I2CBus *bus, uint8_t address, uint32_t 
> > rom_size,
> > +                                const uint8_t *init_rom, uint32_t 
> > init_rom_size);
> >   #endif
>